The present invention relates to a protective casing for housing an electric component and for providing electric conduction between the electric component and an external object. It also relates to a rechargeable battery pack using such a protective casing.
A prior-art rechargeable battery pack used for electric equipment such as a mobile phone has such a structure as shown in FIGS. 5 and 6. The rechargeable battery pack 101 includes a casing body 101A and a lid 101B. The casing body 101A is upwardly open and has a side wall 110 formed with a through-hole 101a. The lid 101B, which is capable of closing the upward opening 112 of the casing body 101A, is formed with a plurality of through-holes 111a. The casing body 101A accommodates rechargeable batteries 102 and a protective circuit board 103.
The protective circuit board 103 functions to prevent the rechargeable batteries 102 from being overcharged. The protective circuit board 103 is electrically connected to the rechargeable batteries 102. The protective circuit board 103 is formed with a plurality of terminals 130 protruding from the surface thereof. When the protective circuit board 103 is housed in the casing body 101A, the terminals 130 protrude outwardly from the casing body 101A via a through-hole 101a. 
The rechargeable battery pack 101 is provided with a plurality of terminal segments 121 extending onto the upper surface of the rechargeable batteries 102. Each of the terminal segments 121 has an end 121a electrically connected to a terminal 120 of a corresponding rechargeable battery 102 and the other end 121b protruding outward from the lid 101B through a corresponding through-hole 111a. 
Thus, it is possible for the rechargeable batteries 102 to be charged from the outside through the terminals 130 and to discharge (to supply power) to the outside through the terminal segments 121.
The through-hole 110a is designed to have a size sufficient for easily receiving a corresponding terminal 130. Each of the through-holes 111a is designed to have a size sufficient for easily receiving the other end 121b of a corresponding terminal segment 121. Accordingly, a clearance is formed around each of the terminals 130 and each of the other ends 121b of the terminal segments 121, which allows communication between the inside and the outside of the casing body 101A. As a result, moisture and/or dust for example may enter from the outside via the through-holes 101a, 111a, which may cause a problem such as shorting in the protective circuit board 103.
To solve this problem, it may be considered that the surface of the protective circuit board 103 may be coated with a resin for example for protecting the protective circuit board 103. However, to perform such an additional step decreases the production efficiency, increases the cost, and further, bars the weight reduction of the rechargeable battery pack 101.
It is, therefore, an object of the present invention to positively protect electric components such as rechargeable batteries and a protective circuit board without increasing the cost.
In accordance with a first aspect of the present invention, there is provided a protective casing for housing an electric component and for providing electric conduction between the electric component and an external object, wherein the protective casing is integrally formed with terminal segments each of which has one end for electrical connection to the electric component, each said terminal segment having another end for electrical connection to the object.
The terminal segments integrated with the protective casing are utilized as a means for providing conduction between the electric component housed in the protective casing and the external object. Unlike the prior art arrangement in which each terminal of an electric component is externally exposed via a through-hole, the terminal segments provide an integral structure together with the protective casing for electrical connection to both the inside and the outside of the protective casing, thereby enhancing the hermetic ability of the protective casing against entry of moisture or the like from the outside. As a result, it is possible to reliably protect the electric component housed in the protective casing from moisture, dust or the like.
The electric component to be housed in the protective casing may be a circuit board which carries semiconductor chips for example, or a rechargeable battery.
According to a preferred embodiment, the protective casing comprises a box-like casing body which is formed by resin-molding to have an opening, and a resin lid for closing the opening, wherein at least one of the casing body and the lid being insert-molded with the terminal segments.
According to another preferred embodiment, said one end of each said terminal segment is exposed or extended internally of the casing body, whereas said another end of said each terminal segment is exposed or extended externally of the casing body or the lid.
According to a further preferred embodiment, the terminal segments include a first terminal segment insert-molded with the casing body, and a second terminal segment insert-molded with the lid, wherein the first terminal segment comes into contact with the second terminal segment when the lid is mounted on the casing body to close the opening.
According to still another preferred embodiment, the second terminal segment is pressed against a terminal of the electric component due to elastic restoration of the first terminal segment.
According an alternative preferred embodiment, the first terminal segment is pressed against a terminal of the electric component due to elastic restoration of the second terminal segment.
According to a still further preferred embodiment, the first terminal segment has a portion extending internally of the casing body, wherein said portion is convexly bent to have an apex for clamping the second terminal segment between the apex and the terminal of the electric component.
According to an alternative preferred embodiment, the second terminal segment has a portion extending internally of the casing body, wherein said portion is convexly bent to have an apex for clamping the first terminal segment between the apex and the terminal of the electric component.
In accordance with a second aspect of the present invention, there is provided a rechargeable battery pack comprising rechargeable batteries, a protective circuit board electrically connected to the rechargeable batteries for protecting the rechargeable batteries, and a resin casing for housing the batteries and the protection circuit board, wherein the casing is insert-molded integrally with terminal segments which are electrically connected to the protective circuit board and/or the rechargeable batteries and are electrically connectable to an external object.
In this rechargeable battery pack, the terminal segments are integrated with the casing by insert molding, and the rechargeable batteries and the protective circuit board housed in the casing are electrically connected to the external object, so that the casing is not formed with a passageway for communication between the inside and the outside of the casing, as opposed to the prior art. Therefore, moisture and dust are unlikely to enter the casing, and hence, it is unnecessary to coat the protective circuit board with a resin for example to prevent shorting in the protective circuit board. Further, since the terminal segments can be mounted at the same time as resin-molding the casing, it is possible to provide electric conduction between the inside and the outside of the casing and to reliably protect the protective circuit board against moisture and dust without causing a decrease of the assembly efficiency and an increase of the manufacturing cost.
According to a preferred embodiment, the protective casing comprises a box-like casing body which is formed by resin-molding to have an opening, and a resin lid for closing the opening, wherein at least one of the casing body and the lid being insert-molded with the terminal segments.
According to another preferred embodiment, said one end of each said terminal segment is exposed or extended internally of the casing body, whereas said another end of said each terminal segment is exposed or extended externally of the casing body or the lid.
According to a further preferred embodiment, the terminal segments include a first terminal segment insert-molded with the casing body, and a second terminal segment insert-molded with the lid, wherein the first terminal segment comes into contact with the second terminal segment when the lid is mounted on the casing body to close the opening.
According to still another preferred embodiment, the second terminal segment is pressed against a terminal of the electric component due to elastic restoration of the first terminal segment.
According an alternative preferred embodiment, the first terminal segment is pressed against a terminal of the electric component due to elastic restoration of the second terminal segment.
According to a still further preferred embodiment, the first terminal segment has a portion extending internally of the casing body, wherein said portion is convexly bent to have an apex for clamping the second terminal segment between the apex and the terminal of the electric component.
According to an alternative preferred embodiment, the second terminal segment has a portion extending internally of the casing body, wherein said portion is convexly bent to have an apex for clamping the first terminal segment between the apex and the terminal of the electric component.
Various features and advantages of the present invention will be apparent from the detailed description of a preferred embodiment given below with reference to the accompanying drawings.